We carried out mapping of the excess carrier lifetime for a bulk p-type 4H-SiC wafer by
the microwave photoconductivity decay (μ-PCD) method, and we compared the lifetime map with
structural defect distribution. Several small regions with short lifetimes compared with surrounding
parts are found, and they correspond to regions with high-density structural defects. Excess carrier
decay curves for this wafer show a slow component, which originates from minority carrier traps.
From temperature dependence of the excess carrier decay curve, we found decrease of the time
constant of the slow component with increasing temperature. We compared the activation energy of
the time constant with that obtained from the numerical simulation, and concluded that the energy
level for the minority carrier trap would be 125 meV from the conduction band.